Method of centrifugal purification of sugar



June 29, 1954 E GI KOCHU ETAL 2,682,488

METHOD OF CENTRIFUGAL PURIFICATION OF SUGAR Filed July 18, 1949 T {Tq -1 r"` tgl- INVENTORS.

, i 6. Koc//L/ ATTURVEY Patented June 29, 1954 METHOD OF CENTRIFUGAL PURIFICATION OF SUG Y Ernest G. Kochli, Scarsdale, N. Y., and Charles A. Olcott, West Milford, N. J.

Application July 18, 1949, Serial No. 105,364

2 Claims.

This invention relates to washing apparatus for centrifugal machines such as are used, for example, in the manufacture of sugar and similar solids and more specifically to methods for controlling the distribution of the washing liquid used with said centrifugal machines.

It is an object of this invention to improve the washing of sugar and the like in centrifugal machines.

When sugar or similar material is treated in centrifugal machines, it is customary to spin the wet massecuite to throw oi the mother liqquor and after this liquor has been spun oif and while the machine is still rotating at high speed, it is the practice to spray wat-er or other washing fluid onto the material. In typical apparatus heretofore used, a single spray for the washing iluid is supported from the curb surrounding the centrifugal basket and all of the sugar is washed by the fluid from this spray.

Applicants have discovered that the sugar washing produced by this prior arrangement is not satisfactory. Some of the sugar shows evidence of being over-Washed (Which means that the grains are unnecessarily dissolved) while other parts are under-washed (which means that they have more color, thus lowering the color standard of the entire batch). The present invention, in one of its primary aspects, relates to the improvement of the color standard of washed sugar and the like.

It is another object of this invention to pro- V duce sugar and the like not subject to the disadvantages just described in the preceding paragraph.

It is still another object of this invention to make more uniform the Washed grains of sugar and the like.

Applicants have also discovered that in purging, that is, in spinning ofl the green syrup before washing, the sugar at the top of the sugar wall is normally of superior quality, requiring relatively little washing, while the sugar at the bottom of the basket contains more impurities and frequently the sugar wall is thicker, requiring more Washing. They have taken advantage of this discovery in the present invention.

The above and related objects are attained in accordance with the invention by providing, as an exemplary embodiment thereof, a sugar spraying apparatus having two or more pipes each with a nozzle for spraying sugar in the basket, each spray being regulated both as to time of application and amount of water applied. One spray is located near the top of thebasket where the syrup is quickly spun off and is started a' predetermined time, say 40 seconds, after the machine is started and stopped at say 45 seconds after the start of the machine, giving a total spraying time of 5 seconds. The spray for washing the lower part of the sugar is started at say 43 seconds after the start, thus giving a little more time to get rid of the green syrup, and stopped at say 50 seconds after the start, thus giving a longer spraying time ('7 seconds) and consequently more washing than is applied to the sugar at the top. If desirable a larger spray nozzle can be used for washing the bottom of the basket in order to get more Water on quickly. Also for a very deep basket, three or more spray nozzles each separately controlled can be used. Each spray nozzle is controlled by a three-port, two position valve operated by a solenoid.

While each solenoid can be manually controlled by a push-button, automatic [control means for this solenoid is also provided in accordance with this invention. An exemplary embodiment of this control means (for a two spray device) comprises a limit switch operated by the movement of the mixer gate, for example, and adjustable electric timer means comprising a master timer and two local timers. The limit switch is located at a point Where it will be operated by the normal movement of the mixer gate used to load the centrifugal. 'I'he Washing cycle does not begin until the gate is closed. Then the master timer runs for a predetermined time according to its setting and energizes one of the local timers which simultaneously energizes its solenoid valve, starting the spraying. A predeterminedl time thereafter the second local timer is started running by the closing of a second circuit by the master timer. This second timer upon its actuation immediately energizes its solenoid and starts its spray. The timers time out at times dependent on their individual adjustments to stop the spraying. Both local timers remain in a timed-out position while the centrifugal is running to spin off the wash water and during the periods of braking and discharging the basket but, if desired and in accordance with wellknown practice, the master timer or controller can be used to control the times of these operations also.

The invention Will be more readily understood by referring to the following description taken in connection with the accompanying drawing forming a part thereof, in which:

. Fig. 1 is a schematic diagram of a rotating basket fora sugar centrifugal machine and spray- -centriiuging cycle.

ing apparatus, including two spaced spray members and control apparatus therefor, for washing the grains of sugar in the basket;

Figs. 2 and 3 are schematic diagrams used to indicate the positions of each of the solenoidcontrolled, three-port valves shown in the arrangement of Fig. 1 when each solenoid is, respectively energized and de-energized; and

Fig. 4 illustrates the sequence of the spraying operations.

Referring more speccally to the drawing, Fig. 1 shows, by way of example to .illustrate the invention, a basket I8 of a sugar centrifugal and associated apparatus for controlling the washing of the massecuite therein at the proper times in each centrifuging cycle. The basket I is surrounded by a suitable outer casing Il which has an opening I2 at the top thereof through which the basket can be loaded with massecuite from a suitable mixer tank (not shown). The basket is supported and rotated by a spindle I3 which is driven by any well-known means such as, for example, an individual electric motor positioned above it. Supported from the outer casing Ii by any suitable means are pipes It and I5 terminating, respectively, inside the basket at spray members I8 and I1 and at valves I8 and I9 outside the basket.

The valve I8 has three ports, one of them leading to the pipe I4, a second being connected by a pipe 20, having a hand valve 2l therein, to a suitable source of washing uid such as a water header 22, and the third one being connected to a drip pipe 23 which may lead to a receptacle (not shown) which can be connected through a pump to the water header. Reference will now be made to Figs. 2 and 3 which` represent schematically the on and ofi positions of the valve I8. In the on position (Fig. 2), washing vfduid from the header 22 is applied, through the open valve 2 I, the pipe 2U, valve I8, pipe I4, hand valve 24, pipe 25 and spray I6, to the sugar grains in the basket I0 at the proper time in each When the valve I8 is turned to the off (Fig. 3) position, the pipe 20 from the valve to the header 22 is blocked and the passage from the pipe I4 to the drip pipe 23 is opened. If the valve I8 is located below the level of the spray member It, the liquid in the spray pipe 25 forms a Siphon which draws the liquid back through this pipe away from the spray nozzle I8, and down through the drip 23, instead of allowing it to dribble on the sugar which has been dried by the centrifugal action of the rotating basket IIJ, as described in Patent 2,461,741 issued February 15, 1949 to E. G. Kochli .and C. A. Olcott.

The valve I8 can be operated by hand between its on and off positions, at the proper times -in each centrifuging cycle, but preferably this operation is accomplished by means of a solenoid 26 which is energized either by a source of power 21 and a manually operated switch 3 operating to connect together contacts 28 and 29,' or by automatic means to be described below after the description of the valve I9 and its connections.

The valve I9 is similar to the valve I8 and the diagrams shown in Figs. 2 and 3 apply to it as well as to valve I8. Valve I9 is connected to the header 22 by means of pipe 20 and to the drip pipe 23. Its third port is conneced through pipe I5 having a hand valve 3i therein to the lower spray nozzle I1. Valve I9 is actuated be- -tween `its on and off positions by means oi solenoid 32 and source of power 33, the circuit ill being closed by manual switch 33 bridging contacts 34 and 35 or by the automatic means to be now described.

When the hand-operated switches are left open (as indicated in Fig. 1) they can be operated by automatic means comprising the master timer 31 and local timer mechanisms 38 and 39, respectively connected Vto operate solenoids 26 and 32 at the proper times in the washing cycle. Timers 31, 38 and 39 are of any suitable form and are sold commercially by a number of suppliers so their internal mechanism and connections need not be described here. Master timer 31 is initiated by the closing of a suitable switch d3 which can be a manually operated switch or a limit switch operated by closing of the gate of the centrifugal mixer (not shown) supplying the basket I8 with massecuite. Closing of the switch 49 supplies power from the lines LI and L2 to the master timer 31 and starts its motor running and at the saine time supplies power over line 4I to start the motor driving centrifugal basket Iii. After a predetermined interval 'from the time the motor of the centrifugal has been started for the drying operation, the master timer 31 closes a set of contacts to apply power over line 42 to start running the motor in timer 38 and over line 43 to start the motor in timer 38. After a second predetermined interval making a total of, for example, 40 seconds after the centrifugal motor has been started, the timer 38 closes a set oi contacts to operate solenoid 2S. This operates valve I8 to the on position and applies spray water from header 22 to the spray nozzle I3, the amount of water being controlled by valve 2d. In the meantime, the timer motor in timer 39 has also been operating and after a total interval of, for example, 43 seconds from the time of starting of the motor of the centrifugal, a set of contacts in this timer is closed and solenoid 32 is operated to move valve I9 to the on position and apply spray water from the header 22 to the lower spray nozzle I1. Power for the timers 38 and 39 can be obtained from the lines LI and L2 or from local sources. The timer motors in timers 38 and 39 run for predetermined intervals of, for example, 5 and 7 seconds, respectively, after closing their contacts (as above described) and then they time-out, opening these contacts and causing the solenoids 28 and 32 to become deenergized and operate the valves I8 and I9, respectively, to the oi positions shutting oiic in turn the nozzles I6 and I1. Fig. 4 shows the periods of operation of the spray nozzles I6 and I1 and the overlapping of these periods of spraying. Both timers 38 and 39 remain timed-out during the spinning oi of the wash water, and during the braking and discharging operations of the basket. The master timer 31 can be used to control these operations, if desired, and timers or controllers for this purpose are well-known.

It is obvious that the specific times of spraying and the durations or" spraying periods are given merely by way of example and can be varied as desired. The amount of water for each spray nozzle can be varied by settings of the hand valves 24 and 3|. One of the nozzles (as, for example the nozzle I1) can be made larger than the other in order to get more water on more quickly. Usually the bottom requires more water than the top. For a very deep basket, three or more spray nozzles, each separately controlled for times of operation and amount o water sprayed, can be used.

By means of the controlled method of spraying described herein, a much more even washing of the sugar can be obtained than in the arrangements heretofore used.

Obviously various changes can be made in the embodiment described without departing from the spirit of the invention the scope of which is indicated in the claims.

What is claimed is:

1. The improvement in the method of centrifugal purification of sugar and the like wherein there is a purging treatment of the sugar ma'- terial in the centrifugal followed by the centrifugal washing of said material, which comprises Washing the top of said material during a period which starts earlier and uses less washing liquid than the period in which the bottom of said material is washed.

2. The improvement in the method of centrifugal purication of sugar and the like wherein there is a purging treatment of the sugar material in the centrifugal followed by the centrifugal Washing of said material, which comprises washing the top of said material during a period which starts earlier, has a. shorter spraying time and uses less Washing liquid than the period in which the bottom of said material is washed.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 518,152 Lach Apr. 10, 1894 1,224,095 Roberts et al Apr. 24, 1917 1,714,232 Morris May 21, 1929 2,089,906 Long Aug. 10, 1937 2,244,652 Kochli June 3, 1941 2,261,914 Hertrich Nov. 4, 1941 2,326,071 Schutte Aug. 3, 1943 2,418,776 Kopplin Apr. 8, 1947 2,427,101 Kochli Sept. 9, 1947 2,461,741 Kochli et al Feb. 15, 1949 FOREIGN PATENTS Number Country Date 576,771 Great Britain Apr. 17, 1946 OTHER REFERENCES McGinnis, Beet Sugar Technology, page 367, Reinhold Publ. Corp., N. Y., 1951. 

1. THE IMPROVEMENT IN THE METHOD OF CENTRIFUGAL PURIFICATION OF SUGAR AND THE LIKE WHEREIN THERE IS A PURGING TREATMENT OF THE SUGAR MATERIAL IN THE CENTRIFUGAL FOLLOWED BY THE CENTRIFUGAL WASHING OF SAID MATERIAL, WHICH COMPRISES WASHING THE TOP OF SAID MATERIAL DURING A PERIOD WHICH STARTS EARLIER AND USES LESS WASHING LIQUID THAN THE PERIOD IN WHICH THE BOTTOM OF SAID MATERIAL IS WASHED. 